Function ExecHashSkewTableInsert

src/backend/executor/nodeHash.c:3123–3162

* ExecHashSkewTableInsert * * Insert a tuple into the skew hashtable. * * This should generally match up with the current-batch case in * ExecHashTableInsert. */

 * ExecHashTableInsert.
 */
static void
ExecHashSkewTableInsert(HashState *hashState,
						HashJoinTable hashtable,
						TupleTableSlot *slot,
						uint32 hashvalue,
						int bucketNumber)
{
	bool		shouldFree;
	MinimalTuple tuple = ExecFetchSlotMinimalTuple(slot, &shouldFree);
	HashJoinTuple hashTuple;
	int			hashTupleSize;

	/* Create the HashJoinTuple */
	hashTupleSize = HJTUPLE_OVERHEAD + tuple->t_len;
	hashTuple = (HashJoinTuple) MemoryContextAlloc(hashtable->batchCxt,
												   hashTupleSize);
	hashTuple->hashvalue = hashvalue;
	memcpy(HJTUPLE_MINTUPLE(hashTuple), tuple, tuple->t_len);
	HeapTupleHeaderClearMatch(HJTUPLE_MINTUPLE(hashTuple));

	/* Push it onto the front of the skew bucket's list */
	hashTuple->next.unshared = hashtable->skewBucket[bucketNumber]->tuples;
	hashtable->skewBucket[bucketNumber]->tuples = hashTuple;
	Assert(hashTuple != hashTuple->next.unshared);

	/* Account for space used, and back off if we've used too much */
	hashtable->spaceUsed += hashTupleSize;
	hashtable->spaceUsedSkew += hashTupleSize;
	if (hashtable->spaceUsed > hashtable->spacePeak)
		hashtable->spacePeak = hashtable->spaceUsed;
	while (hashtable->spaceUsedSkew > hashtable->spaceAllowedSkew)
		ExecHashRemoveNextSkewBucket(hashState, hashtable);

	/* Check we are not over the total spaceAllowed, either */
	if (hashtable->spaceUsed > hashtable->spaceAllowed)
		ExecHashIncreaseNumBatches(hashtable);

	if (shouldFree)
		heap_free_minimal_tuple(tuple);
}

/*
 *		ExecHashRemoveNextSkewBucket